Spark plug shorting device



Jan. l1, 1955 C, KAMOWSKI 2,699,527

SPARK PLUG SHORTING DEVICE Filed Jan` 8, 1952 United States Patent O SPARK PLUG SHORTING DEVICE Charles Kamowski, East Orange, N. J. Application January 8, 1952, Serial No. 265,446 2 Claims. (ci. 324-19) rThis invention relates to an improved device for short circuiting spark plugs of an internal combustion engine, whereby not only to discover defective plugs, but also to control the ignition system of the engine for testing operations with respect to selected cylinders of a multi-cylinder engine.

ln modern internal combustion engines, for weatherproofing and like protective purposes, electrical connection of the spark plugs in the ignition system is made by insulated circuit wires terminating in coupling contacts which telescopically engage over external terminal posts of the spark plugs which deliver electrical energy to the sparking electrodes, one of which is grounded. Each circuit wire coupling contact is wholly enveloped in a hood of insulating material, such as rubber, so that, when engaged with the terminal post of a spark plug, the post is entirely enclosed within the insulating hood, and therefore is not exposed subject to engagement by an externally applied short circuiting means, such as a screw* driver, whereby to directly ground the post to the engine cylinder block.

This invention has for an object to provide a spark plug sini-ting device which is especially adapted for use in connection with the above described modern type of spark plug coupling to the ignition system.

The above and other objects of this invention will be understood from a reading of the following detailed description thereof in connectionv with the accompanying drawings, in which:

Fig. l is a front elevational view of the spark plug shorting device according to this invention; and Fig. 2 is a side elevational view of the same, viewed from the right in Fig. l.

Fig. 3 is an elevational View, in part section, showing the operative application of the shorting device of this invention to a spark plug and to the coupling connection of an ignition circuit wire by which said plug is served.

Fig. 4 is a schematic View showing the shorting devices applied to the several spark plugs of a multicylinder engine, subject to manipulation for testing operations with respect to selected engine cylinders.

Similar characters of reference are employed in the above described views, to indicate corresponding parts.

The spark plug shorting device of this invention is adapted for use in connection with spark plugs of modern type, an illustrative form of which is shown in Fig. 3, and generally indicated by the reference character 10. Said spark plug 1t) comprises a metallic body 11 adapted to be threaded through a cylinder head wall 12 of an internal combustion engine. Extending through the body lll, and insulated therefrom by an insulator sleeve 13, is terminal post 14 which projects exteriorly from the outer end of the body 11, and which terminates at its free end in a contact head 15 of suitable conformation. Said terminal post 14 conducts electrical energy to one electro-'le 16, which projects from the inner end of the body .n spaced spark gap relation to a cooperating electrode 1"!" which is grounded through the body 10 to the 4engine cylinder block.

A spark plug of the above described type is con nectcd to the ignition system of the engine by a service wire 13 which terminates in a female contact member 1f having resilient portions 20 which can be sprung or snapped over the contact head 15 of the spark plug terminal post 1li, so as to both mechanically and electrically couple the service wire to the latter. The service wire 18 is covered by flexible insulation 21 which terminates in an elastic hood member 21' within the upper interior of which said female Contact member 19 is enclosed. Said hood member 21 is so formed and proportioned that, when the service wire is coupled to the spark plug terminal post 14, the latter will be entered within the hood member so as to be protectively enveloped thereby.

The spark plug shorting device of this invention comprises an elongated body 22 formed from a suitable electrically conductive metal. Said body 22 may be of any suitable shape, but is preferably cylindrical, having a tapered upper end as shown. Projecting axially upward from the upper end of the body 22 is a terminal post 23 which terminates in a contact head 23. This terminal post and its contact head corresponds in conformation to the conformation of the spark plug terminal post 14 and its contact head 15. Extending upwardly into the body 22, from its lower end, is an axial bore or socket 24, which corresponds in diameter to the diameter of the spark plug terminal post 14, whereby the body 22 can be telescopically engaged over the latter in electrically conductive attached relation thereto.

Aixed to the body 22 of the shorting device is a yieldable latch piece 25 which is made of spring wire or spring strip material in a substantially Vshape to provide a latch nosing 2.6 having a downwardly and rearwardly inclined cam leg 27. This latch piece 25 is disposed to extend laterally through a slot or opening 28 formed in the side wall of the bore or socket 24 of body 22, so as to position its latch nosing 26 within the interior of said bore or socket 24 adjacent to a sidle and inwardly above the open end or mouth thereof. Preferably, and by way of illustration, said latch piece 25 is provided with a base portion 29 in the form of an eye member adapted to overlie the exterior surface of the body 22 above the slot or opening 28, and to be affixed to said body by a fastening screw Sil which is passed through said base portion and screwed into said body. It will be understood, however, that the latch piece may be axed to the body 22 in any other suitable or convenient manner.

Pivotally supported by the fastening screw 30, or other equivalent pivoting support, whereby to mount the same on the body 22 in electrically conductive attached relation thereto, is a movable grounding contact blade 3l of resiliently liexible character. Said contact blade is preferably provided with a linger piece or knob 32 by which it can be manipulated; the same being suitably affixed to the blade intermediate the ends of the latter, and being preferably made of electrically non-conductive material, or suitably insulated from electrical Contact with said blade. The contact blade 31, being pivotally mounted on the body 22, can be moved at will to either an operative or inoperative position, as will be understood from the following description of the operation of the shorting evice in use.

To apply the shorting device of this invention to a spark plug in electrically connected relation to the service conductor 13 of an ignition system by which the spark plug is normally served, said service conductor is rst detached from the terminal post 14 of the spark plug, whereupon the shorting device is coupled to the spark plug by engaging the body 22 of the former over the terminal post of the latter. in so doing, the spark plug terminal post lli is caused to enter the bore or socket 24 of the body 22 so that the contact head 15 of said terminal post will be moved past the latch nosing 26 of the latch piece 25. During such entering movement of the spark plug terminal post 11i, the Contact head 15 thereof, by its upward thrust against the cam leg 27 of the latch piece 25, will cause said latch piece to yield to the upward passage of said contact head 15, and, after the contact head passes the latch nosing 26, the tension of the latch piece will cause inward movement thereof, whereby to engage the latch nosing beneath said contact head, thus releasably latching the body 22 in electrically conductive coupled relation to the spark plug terminal post 14. After the body 22 is thus attached to the spark plug to be served thereby, the service conductor 1E is connected to the terminal post 23 of said body 22 by entering said terminal post in the hood member 21 of the service conductor inslation, whereby to engage the female contact member 19 with the contact head Z3 of said terminal post, and thus to again electrically connect the spark plug through the shorting device to the ignition system by which said spark plug i`s 'served (see Fig. 3). l

When the shorting device is operatively coupled to a spark plugL as above set forth, if it is desired to prevent delivery of electrical energy through the spark plug electrodes, in other words to short the spark plug, the movable contactV blade 31 is manually swung down to bring the same into contact with the grounded body l1 of said spark plug, wherby electrical energy flows from the body 22'through the contact blade 31 `directly to ground, and thus by-passes said electrodes so that the spark plug becomes inoperative (see Fig. 3). If it is desired that thespark .plug be put in operative condition, the contact blade is swung to any position which holds the same disengaged from grounding contact with the body 11 ot the spark plug.

In use of the short-ing devices of this invention to test spark plugs of a multi-cylinder engine, a shorting device is applied to each spark plug in the manner above described (see Fig. 4) and then all but selected spark plugs to be tested are shorted, whereby to determine whether the tested plugs are 'functioning properly. The sparkV plugs may be selectively shorted for engine trouble determination in addition to plug testing, such as testing for defect-ive or sticky valves, leaky piston rings, piston slap, bearing knocks, wrist pin knocks, and like faults.

When lthe spark plugs of a multi-cylinder engine are each equipped with a shorting device of this invention, the cylinder balancing test apparatus well known to the art can be connected to the engine, whereupon selected spark plugs can be quickly and easily shorted out by grounding the same4 by means of their manipulatable contact blades 31, whereby to operate the engine on selected cylinders the spark plugs of which are not grounded. This is done by 'testing the cylinders in accordance with the firing sequence thereof. For example, as shown in Fig, 4 wherein the Vtiring sequence of a six cylinder engine is indicated by the `lower row lof cylinder designating numbers, cylinders 5, 3, 2 and 4 are shorted so that the engine runs on cylinders 1 and 6, thus permitting balance of these cylinders to be tested. Test of cylinders 1 and 6 having been completed, the spark plugs thereof are grounded, and spark plugs of cylinders Sand 2 are rendered operative by disconnecting the contact arms 31 of their shorting devices from ground, so that the engine then runs on said cylinders 5 and 2 subject to balancing test thereof. Similarly,

cylinders 3 and 4 can next be subjected to balancing test 9;;

by grounding all spark plugs but those of these cylinders.

Having now described my invention, I claim: l. Shor'ting device for 4interposition between a spark plug having an external terminal post and an ignition Wiring connection enclosed by enveloping insulation, said shorting device comprising an electrically conductive body having an axially extending terminal post at its upper end extending axially into its lower end portion and adaptedV to receive the external terminal post of said spark plug, said body having a side opening communicating with its said socket, a resilient cont-act means aixed to said body to extend inwardly through said side opening thereof into electrically conductive engagement with a spark plugterminal post entered in said body socket, and an external contact blade pivotally mounted on the side of said body intermediate its ends and in electrically conductive connection therewith, said contact blade being swingable about its pivotal connection with the body to and from a grounding contact engagement with the spark plug.

2. A shorting device for interposition between a spark plug and an ignition wiring connection `enclosed by enveloping insulation, said spark plug having an annularly grooved, axially projecting, terminal post defining a contact head aty its free end, said shorting device comprising an electrically conductive body provided at its upper end with an axially projecting, annularly grooved, terminal post defining a contact head which substantially corresponds in conformation to that o the spark plug terminal post, whereby to be engageable by the insulation enveloped ignition Wiring connection by which the spark .plug is to be served, said body also having a socket extending axially into its vlower end and adapted to receive the terminal `post of said spark plug, said body having a side opening communicating with vits said socket, a resilient latch-piece aixed to said bodyl to extend inwardly through said side :opening thereof, said latch-piece having a latchnosing adapted to engage beneath the contact head of 4a spark plug terminal post entered in said body socket, whereby to releasably lsecure the body in operative attached relation to said spark plug terminal post, and an external contact blade pivotally mounted on the side of said body intermediate its ends and in electrically conductive connection therewith, Asaid contact blade being swingable about its pivotal connection with the body to ailid from a `grounding contact engagement with the spark p ug.

References Cited in the le of this patent UNITEDl KSTATES PATENTS 1,107,498 Dalitz Aug. 18, V1914 1,509,224 Berthold Sept. r23, 1924 FORElGN PATENTS 116,371 Australia Dec. 30, 1942 

